1. Field of the Invention
The present invention relates to a switching apparatus for a switched network of the asynchronous transfer mode (ATM). The switching apparatus according to the present invention is used for high speed transmission of data, such as voice, text, picture and the like, in a digital communication system, such as the integrated services digital network (ISDN).
2. Description of the Related Arts
In general, during the operation of a switching apparatus of a switching network of the asynchronous transfer mode, first, a signal is preliminarily sent to a decoder for the input interface board in the path inspection control device and the control of a central processing unit, and a first input line is connected to the test side. In the first test cycle period, comparison data is set in the comparison data register in the path inspection control device; output line data is set in the output line data register; a signal is sent to the decoder for the output interface board; the line of the output line data is connected to the test side, and cell data is set in the register for the header and information. The cell data is made to be a cell for path inspection, and the produced cell for path inspection is delivered. If the operation of the switching apparatus of a switched network of the asynchronous transfer mode is normal, the cell for path inspection passes through the first path and is latched in a latch member. The data of the latch member and the data of the comparison data register are compared in a comparator, and, if the data coincide, a signal indicating normality is sent to the central processing unit.
In the second test cycle period, comparison data is set in the comparison data register, the second output line data is set in the output line data register; a signal is sent to the decoder for the input interface board; the second output line of the interface board is connected to the test side, and a cell data is set in the register for header and information. The cell data is delivered as a cell for path inspection by the cell generation member, and, if the operation of the switching apparatus for a switched network of the asynchronous transfer mode is normal, the cell for path inspection passes through the second path, and is latched in the latch member. The content of the latch member and the content of the comparison data register are compared by the comparator, and, if the content of the latch member and the content of the comparison data register coincide, the normality signal is sent to the central processing unit.
In a similar manner, the processes are carried out up to the n-th test cycle period.
After that, a signal is sent to the decoder for the input interface board by the central processing unit; the second input line of the interface board is connected to the test side, and the processes of the first test cycle period to the n-th test cycle period are similarly carried out. After that, the similar processes of test are carried out until the n-th input line of the interface board is connected to the test side, and accordingly, the process of inspection is completed.
Thus, in the prior art switch apparatus for a switched network of the asynchronous transfer mode, the time required for the inspection of the entire paths is extended to n.sup.2 .times.t, where the time of the process of one test cycle period is t.